This invention relates to envelope drying machines, and more particularly to an improved drying wheel apparatus for effectively drying the envelope closure flaps to prevent adjacent envelopes from adhering together when stacked.
Drying apparatus has been employed in conjunction with envelope machines for many years. Such apparatus in its most prevalent form utilizes a belt or chain conveyor on which the envelopes are carried and the gum dried, before the envelopes are transferred to stacking and counting apparatus. This type of drying apparatus is generally satisfactory where the adhesive used is of a rapid drying type. However, for gum adhesives, particularly those of the pressure sensitive variety which dry relatively slowly, a smaller, more compact means having improved provisions for accelerating the drying process is desirable for use with high capacity envelope machines.
This requirement has led to the development of conveyor wheels rather than belts to carry the envelopes during the drying process. However, there have been two problems associated with this type of device. One is the provision of an efficient drying means and the tendency has been to blow drying air outwardly from a central manifold but this has not proven satisfactory. Another problem is the suitable holding of the envelopes, during the drying process, against the tendency for them to move outwardly under centrifugal forces when the drying wheel is rotating at relatively high speed.
The present apparatus solves these and other problems in a manner not disclosed in the known prior art.